This invention relates to braiding machines and more particularly to a fast-moving eyelet guide for use in such machines in which multiple strands or filaments are being simultaneously payed off from each spool, these multiple strands not being twisted together.
Braiding machines, for example, the Wardwell braiders, have been used commercially for many years, probably for at least sixty years, and can be used to apply a braid layer of wire strands around an electrical cable for protecting the inner conductors of the cable, for shielding the cable, and often for providing a grounded outer conductive sheath for the cable. Such braiding machines are also used to form a braid or to form a braid layer around a core, for example to braid glass strands around an electrical conductor.
The Wardwell braiding machine normally includes an upper and a lower revolving carriage each of which contains a plurality of supply spools of strands, for example eight upper spools and eight lower spools. The strands from all of these spools are fed together for forming the braided layer around the electrical cable.
All of the upper and lower spools contain the same number of strands. For example, in the braiding of wire strands around an electrical conductor in the prior art, each spool contains a number of wire strands in the range from 3 to 9.
The wire strands from the respective upper and lower supply spools are interweaved by the machine to form the braiding around the cable. Since the clusters of wire strands are unwound from the respective individual supply spools, guide apparatus must be provided for each spool in order to align and feed the cluster of wire strands together at the proper direction for producing the interweaving braiding action.
FIG. 1 illustrates a prior art inclined wire strand guide roll as associated with each of the lower supply spools in a conventional Wardwell braiding machine. The cluster of wire strands 22 from the spool travels up and down along this guide roll. This high speed movement unpredictably allows the individual unrestrained strands to become separated from each other, as will be understood from FIG. 1. The individual strands respond to their individual tensions and to their individual friction effects, thus allowing them to become spread apart irregularly as they proceed to be subsequently moved by horizontal guide cam components in the braiding machine. The strand or strands which separate from their neighbors are vulnerable to snagging or missing the upward and downward transpositions required by the horizontal guides in the braiding machine, which unpredictably causes one or more of the strands to break quite often. Such frequent breakage considerably slows the braiding process, makes it expensive and prevents the production of a long braided product. A coaxial cable product must be cut to length whenever a broken strand occurs, because the coaxial cable should not have a braid layer containing broken strands. I have found that using the prior art wire guide apparatus illustrated in FIG. 1 on a Wardwell braider causes a wire strand or several strands to break on an average of every few hours or so, and usually more than one strand breaks at the same time.